Improvement in lamps for streets



e shreeitSL-sher 2. Street Lamp.

Patented 1an. 2,1872.4

THOMAS A. SKELTON. N0. 122,409.

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NOVZQ. Patenltedlan.2,1872.

6 Sheets--Sheet 4.` Street Lamp.

Patented Jan. 2, 1872.

THOMAS A. SKELTON.

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THOMAS A; SKELTON. I' street Lamp. N0. 122,409. Fa'tentedjan.2,1872.

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THOMAS ALFRED SKELTON, OF COUNTY OF' MIDDLESEX, ENGLAND.

IMPROVEMENT IN LAMPS FORSTREETS, &c.

` Specificationpforming part of Letters Patent No. 122,409, dated January 2, 1872.

To all` whom it may concern:

4Be it known that I,THoMAs ALFRED SKEL- TON, of No. 37 Essex street, Strand, in the county of Middlesex, England, a subject of Y the Queen of Great Britain, have invented or discovered new and useful improvements in lamps fixed in streets, open spaces, factories, railway stations, and public buildings, and I, the said THOMAS ALFRED SxnLroN, do hereby declare the nature of the said invention and in what manner the samevis to be performed front of the point of light and at such angles with regard to the point of light according to the well-known laws of the reiiection and re- Y fraction of light as will intercept and utilize by reflection or refraction certain rays of light otherwise uselessby reason either of their vertical elevation or direction and in herrn etieall y `or otherwise sufficiently inclosin g such reflectorsprisms,v or prismoids, between plates of glass both as a protection from dust and moisture, and to economise labor in cleaning. This improvement in lamps is specially applicable to street-lamps, and other such lamps fixed in parks and open spacesJ and in railway stations,

factories, buildings, and places where the rays of light ascending above the level of the lamp are practically useless and wasted.

Having thus described the nature of my said invention, I will now proceed to describe the manner in which I propose to carry the same into effect; and for the purpose of more clearly describing the same 1 will use the drawing hereunto annexed,- in each of the iigures of which the same letters of reference indicate similar parts.

f I wish, however, it to be understood that l do not coniine myself to the precise details ,shown in the said drawing so long asA the distinctive characteristics of my invention are adopted. Iwish, however, here to state that my invention is applicable to lamps, such as I have above mentioned, ofany form or shape,

i and to such lamps Whether already constructed and in use, as "also, to lamps of which this invention or improvement may hereafter form part of the original construction, and it may, also be applied to one or more sides of any such lamp.

The materials in which this improvement in lamps may be executed are as follows: The reiiectors may be of any suitable material having a reflecting surface.v Thin silvered glass manufactured by a new process and known as patent silvering,7 the glass being silvered by a deposit of silver in solution, and not bythe quicksilver process,7 is preferable, it being av brilliant reiiector unaffected by a high teinperature, and protected by a red-lead coating on the silvered'side. The prisms or prismcids should be of a clear transparent glass, and rnay be cast in molds of the required form, and iireglazed,7 or cutland polished if the greatest effect is required and expense not an object. The inclosing glass plat-es should be of iatted crown-glass or of the fifteen ounce-or twenty-one ounce sheet-glass of the usual glazing quality; and where colored illumination is required either or both of these plates may be colored glass. The frame and fastenin gs should be of metal, ,east or stamped or manufactured of sheet or rolled metal in the ordinary way for similar metal cases to the required form; and if of iron thenalso tinned or galvanized. The adjusting-screws and appliances should be of metal. The retlectors, prisms, prismoids, and glass plates may be xed or secured in red lead, putty, or in other similar cement 5 whitevlead and varnish-putty has the advantage of not discolorin g.

Figure l represents the vertical section of an ordinary street-lamp with cases of reiiectors constructed according to my invention, taking the place of part ofthe usual glazing, (which is to be removed so far as the cases extend,) and in this application placed on two sides to reiiect the light in the direction of the length of the street. B represents the highest point of light in the iiame. O O are the otherwise useless direct rays of light emanating from the iiame, which, by this invention, l divert and utilize. D D D are the reiiectors intercepting the above-mentioned rays of light G C. E it are the above-mentioned rays of light C C after reilection, by which they have been divert view or elevation of the same case.

2 e A r 122,409

ed into a new direction. F F are the useful direct rays of light which are not affected by this invention. In this forni ot' lamp of the usual size it is advisable to let B, the tlame or brightest point of light, be about six inches from the bottom ofthe lamp-frame, so that the under side of thcy upper case may not be overhe'ated or blackened by the iiame. For ordinary steet-lamp purposes and to meet the necessities of various positions requiring the light to be reflected to a greater or less distance, or at greater or less angles, it will be advisable to construct these cases oi reliectors upon a scale estimated-to reiiect at angles either of 65, 70, 75, 80, 55, and 90 degrees, as shown on Fig. 2; and for intermediate or greater or less angles where specially required. In Fig. 2, I have represen teda series ofstreet-lanips placed on ground of dii'erent degrees of slope for the purposes of illustrating the necessity of varying the angles of the reflectors. rlhese angles must vary with the distance of the lamps apart from each other. A simple method ofascertaining with practically-suflicient accuracy the position in which to tix each separate reflector is described in Fig. 3, in which the outlines of the lamp are represented by dotted lines. B represents the point of light, B O, the line or direction ofthe highest ray of light intended to be reflected, P Q, the angle at which it is required to reiiect the light; G G G G, the position of the intended inclosin g glass-plates. Then at a, the point of intersection of the lines B O and l) Q, set oli any equal distance on those lines in the direction ot' B and Q, and a line drawn through those points, say c and b, will'be parallel to the required angle of the reiiector D which is to be placed in this position. N ext draw a line from B to g, the outer edge of the reliector, and the point d where that line intersects the inner glass plate will be the position of the inner edge ofthe next reflector; then set oft', as before, equal distances on the line ot' the ray or' light B d, and on the angle of reiiection required, d f, and drawing a line through the points e j' place the second reiiector parallel to the line ef, and proceed as before. For an glcs ot' greater inclination downward from the lamp, proceed as indicated at It h, Fig. 3. The angle ot' inclination at which the root-case A, Fig. l, should be constructed so as to secure the maximum eit'ect of reflection should approximate to a line at right angles with the plane ofthe center retlecting surface in the upper or roof-case A, as in Fig. l. A mode or' construction suitable for ordinary street-lamps is explained in detail in sheet No. 3, Fig. et, representing a vertical section ofthe uppercase A.

Fig. 5 represents a horizontal longitudinal section ot' the same, and Fig. (i a front exterior Fig'. 7 shows a vertical section of the side case A a. Fig. 8 represents a horizontal or longitudinal section of the same, and Fig. 9 a i'ront exterior view or elevation of the same case, to all of which figures the following letters land lreferences apply.

D D D are the reflectors, G G G, the inclosing sheets of glass; H- H, the metal frame; I I I I, the grooves in the interior sides ofthe -metal case to receive the ends of the reflectors; J J J J, the joint or' red-lead or other suitable material to render the case air-tight and exclude dust or moisture 5 KK, the pins or screws to secure the sheets of glass in their places; "L L, the part ofthe lamp-frame to which the case may be ixed by clip Y or wedge or pin and loop M, or by screws or other suitable means; M M, the wedge or pin and loop; N, the glass ritted to the lower part oi' the side of the lamp in the usual way, Y Y, copper clips riveted to lamp-frame and bent over the iiange Z of the cases to secure them in position 5 and Z, iiange part oi'case by which it may be secured to lamp-frame, and which will also allow or compensate for variations in size of lamp-frames. The vertical 'concentration or dispersion ofthe rays ot' light reiiected may Y be accomplished either by arranging each separate reliector to reflect at an angle oi' inclination varying from the others, or dispersion by forming all the reflectors with surfaces slightly concave, convex, or tinted in a horizontal direction, as shown in Fig. 10, a transverse section of a concave silver-glass reiicctor, Fig. ll, a transverse section of a convex silvered glass'reilector and Fig. l2 a transverse section or' a iiuted or corrugated silver-glass reiiector; or dispersion may be effected by forming one or both of the inclosing glass plates Got' clear tinted glass with the iiutings put in a horizontal direction. The horizontal dispersion ofthe light reiiected may be usefully employed where the lamp is required to give light in all directions, as in lamps iixedat cross-roads and in open spaces, and this dispersion may be ei'ected by forming each reflector with a verticallyiiuted surface, as in Fig. 13, a longitudinal section of a single silver-ed glass retlector; and in Fig. 14, a horizontal section through the lamp D, being the iiuted reii ector or by forming one or both of the inclosin g glass plates G of clear'l iiuted glass, the iiuting placed vertically, and by placing the reflectors alternately slightly inclined to the right and left out of the parallel horizontal line.

The liereinbefore-contained details, illustrations, and examples of this invention have related exclusively to lamps in which the separate reflectors are iixed and immovable in their respective positions in their several inclosing cases. It may be found useful or necessary to construct lamps in such a manner thateach set of reiiectors may be, from time to time, capable of adjustment to any required angle, as illustrated at Figs. 27 and 28, and in which it may also be convenient to have the power to vertically concentrate or disperse the rays of reflected light.

This invention may be applied to lamps whose inclosing sides or tops are globular, circular, or curved in form, by using prisms or prismoids D d and X, or curved metal redectors D of the required shapes and curves inclosed between curved glasses, as shown in Figs 18 and 19; or by constructing the cases With curved glass on the exterior and fiat glass.

toward the light, as shown in Fig. 20, in which case flat reectors may be used in the manner hereinbefore described for ordinary streetlamps, as shown in Figs. 20 and 22; as they also may in lamps Whose tops are square or angular on plan; but of curved glass in the vertical section, as described in Figs. 23, 24, 25, and 26.

The same or similar mechanical construction of the inclosing cases and ttings will apply to these curved forms of lamps with sockets in the'frame Hof a proper form to receive the ends of the prisms or prismoids instead of the grooves applicable to reflectors.

For-indoor or factory purposes or other such employment of light, these cases of relieetors Y may be fitted to utilize the otherwise-Wasted rays of light Without the necessity for any lamp-casing, it being only necessary to" suspend or x the cases of reectors above the light in the position for Which they are to be constructed.

Prisms or prismoids of glass may be einv ployed in all cases instead of reflectors, if desired, it being necessary to place one side of the prism or prismoid ,at the same position and angle as the rei'iecting surface Would have occupied as D d, in Fig. 18. A combination of reiiectors or prisms or prismoids used to reflect light, and prisms or prismoids placed so as to refract light may be employed where it is desired; also to utilize therays of light Whose` direction differs onlyI slightly from the direction in which itis required to divert them, as

shown in Fig. 18, where X represents a prism or prismoid diverting the light by refraction,

and D d prisms or prismoids diverting light by reflection. An additional saving of light may be effected by causing the surfaces of the metal inclosing cases, the backs of the reflectors and the interior surfaces of the lamp frame-work to be White; these surfaces, being illuminated by the iiaine, will be reflected at various angles by the reflectors.

To avoid condensation taking place on the inner surfaces ofthe inelosing glass plates, and

so partly obscuring the rays of reiiected light, care must be taken that the air inclosed Within the sealed cases is perfectly dry, and that the putty or cement used inside is set and hardened, and of such composition that no vapor may be produced from it by the heat to Which the case will be subjected When in use. It may alsobe advisable to place Within each case some fragments of quick-lime to absorb and fix any moisture accidently inelosed, or When difficulty is found in artificially drying the air.

And no W, havin gA described the nature of the said invention and the manner inv which it is to be effected and performed, I declare that What I claim asmy invention, is-

rI he manufacture, application, and use, for the purposes hereinbefore mentioned, of reflectors or glass prisms or prismoids, or of a combination of reecto'rs, prisms, or prismoids hermetically or otherwise sufficiently inclosed between plates of glass, as hereinbefore described and represented on the severalsheets of the drawing hereunto annexed.

T. A. SKELTON. Witnesses:

G. F. WARREN, WILMER M. HARRrs, (90) Both of No. 17 Gmcahurch street, London. 

